<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <h1>hello</h1>
    <form action="/index" method="post" enctype="multipart/form-data">
        <p><input name="user" type="text" placeholder="用户名" /></p>
        <p><input name="pwd" type="password" placeholder="密码" /></p>
        <p>
            <input name='code' type="text" placeholder="验证码" />
            <img src="/check_code" onclick='ChangeCode();' id='imgCode'>
        </p>
        <input type="submit" />
    </form>
	<script type="text/javascript">

	    function ChangeCode() {
            var code = document.getElementById('imgCode');
            code.src += '?';
        }
    </script>
</body>
</html>